Disclosed herein is a silver nanoparticle ink composition. In embodiments, disclosed herein is a silver nanoparticle ink composition particularly suited for pneumatic aerosol printing applications.
Conductive inks are desired for fabricating conductive patterns for electronic device applications.
Xerox® Corporation has invented a nanosilver particle which is stabilized by an organoamine U.S. Pat. No. 8,765,025, which is hereby incorporated by reference herein in its entirety, describes a metal nanoparticle composition that includes an organic-stabilized metal nanoparticle and a solvent in which the solvent selected has the following Hansen solubility parameters: a dispersion parameter of about 16 MPa0.5, or more, and a sum of a polarity parameter and a hydrogen bonding parameter of about 8.0 MPa0.5 or less. U.S. Pat. No. 7,270,694, which is hereby incorporated by reference herein in its entirety, describes a process for preparing stabilized silver nanoparticles comprising reacting a silver compound with a reducing agent comprising a hydrazine compound by incrementally adding the silver compound to a first mixture comprising the reducing agent, a stabilizer comprising an organoamine, and a solvent.
U.S. patent application Ser. No. 13/866,704, which is hereby incorporated by reference herein in its entirety, describes stabilized metal-containing nanoparticles prepared by a first method comprising reacting a silver compound with a reducing agent comprising a hydrazine compound by incrementally adding the silver compound to a first mixture comprising the reducing agent, a stabilizer comprising an organoamine, and a solvent. U.S. patent application Ser. No. 14/188,284, which is hereby incorporated by reference herein in its entirety, describes conductive inks having a high silver content for gravure and flexographic printing and methods for producing such conductive inks.
Solution processable conducting materials including silver nanoparticle inks play an important role in electronic device integrations. Conductive inks that can be easily dispersed in suitable solvents and used to fabricate various conducting features in electronic devices such as electrodes and electrical interconnectors by low-cost solution deposition and patterning techniques including spin coating, dip coating, aerosol printing, and ink jet printing technologies are particularly desired. Aerosol printing, such as with a pneumatic atomizer, can be a low cost and efficient printing process for manufacturing large numbers of electronic devices such as RFID (Radio Frequency Identification) tags, antennas, electronic sensors, and the like.
However, pneumatic aerosol printing usually requires nanoparticle inks with a very high silver content, such as greater than about 60 weight percent, and a viscosity between about 8 and about 30 centipoise for high throughput and efficient printing. A problem with certain currently available nanoparticle conductive inks is the appearance of shortfalls in print performance as a result of changes in ink rheological properties over time, poor ink stability, and/or unpredictable performance characteristics. These issues can result in increased ink cost as ink batches may be rejected for not meeting performance requirements. Unpredictable shelf life can also occur even for certain ink batches initially passing quality checks.
Currently available conductive inks are suitable for their intended purposes. However a need remains for improved conductive inks. Further, a need remains for improved, stable conductive inks that meet the requirements for pneumatic aerosol printing processes for low cost electronic device applications.
The appropriate components and process aspects of the each of the foregoing U.S. Patents and Patent Publications may be selected for the present disclosure in embodiments thereof. Further, throughout this application, various publications, patents, and published patent applications are referred to by an identifying citation. The disclosures of the publications, patents, and published patent applications referenced in this application are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains.